DosBox is buggy with int 15h ah = 86h

I am currently working on an assembly program, but I need to make the program wait every once in a while.

So, I have been using int 15h/ah = 86h, but for some reason DosBox is giving me a hard time, and the program either gets confused with pixels (wierd colors) or in the worse case; crash.

Can someone please help me?

Solution

I had this issue as well. Based on the answer at Problems with BIOS delay function (INT 15h / AH = 86h), I was able to get it working by making sure to set AL to zero before calling the interrupt:

    mov     counter, 10
L1:

    mov     cx, 0007H
    mov     dx, 8480H
    mov     ah, 86h
    mov     al, 0
    int     15h

    mov     dl, '*'
    mov     ah, 02h
    int     21h

    dec     counter
    jnz     L1

(the program prints 10 *'s, pausing for 1 second between each.) With out the 'mov al, 0', the program would hang or give other undefined behavior while DOSBox spews illegal read/write messages. By setting al to zero, the program works correctly but, strangely, error messages still appear on the DOSBox log.